


Gaster Blaster Children

by Quinis



Category: Undertale (Video Game)
Genre: Babyblaster AU, Babyblaster's fluff week, Gen, I blame spacegate
Language: English
Status: Completed
Published: 2016-03-06
Updated: 2016-03-06
Packaged: 2018-05-25 00:45:16
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,122
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6173299
Author URL: https://archiveofourown.org/users/Quinis/pseuds/Quinis
Summary: <blockquote class="userstuff">
              <p>Gaster was experimenting on Subjects P and S when something went wrong. Or right.<br/>Suddenly finding himself wanting to end the project for the children's sake, Gaster brings the two subjects into his home.<br/>Might be a mistake but, he can't really say 'no' now.</p>
            </blockquote>





	Gaster Blaster Children

**Author's Note:**

  * For [KeetahSpacecat](https://archiveofourown.org/users/KeetahSpacecat/gifts).



> This. Is all. Spacegate's fault!  
> Anyway, I stalk the [Babyblasters ](http://babyblasters.tumblr.com/)tumblr and Spacegate declared a fluff week. Would have been fine, if said week didn't come complete with prompts.  
> This one: _At a crucial moment, Gaster suddenly grows a conscience and decides to treat Sans and Pap like actual real monsters. In order to atone for what he almost (but didn’t!) do, he spoils them rotten_ , grabbed me.  
> It's kind of/sort of fluff? I really tried but it turned into snarky Gaster and smug Sans (Papyrus is Papyrus). It was just fun to write.
> 
> So much for not posting any Undertale stuff... *sighs and tries to hold back the floodgates - possibly succeeds? (only time will tell)*

 It wasn’t the tears and begging that got to him.

 It wasn’t the quiet compliance, which was actually helpful.

 It wasn’t even the constant insistence from Subject P that he could be good.

 _‘Why was he doing this?’_ It was his life work! Monsters with SOULs to rival humans! Monsters with greater and more powerful forms!

 The Gaster Blaster Skeletons!

 And yet…

 Yet…

 Subject P looked up at him with orange BRAVERY flickering desperately in his eyes. In his arms, he cradled Subject S’s blaster head. Subject P’s bones trembled audibly as his fingers traced comfortingly over the ridges in Subject S’s blaster head.

_‘Why was he doing this?’_

* * *

 

 Gaster was ready. He had brought Subjects S and P into the room. The three stood before what looked like a giant monster skeleton head. Subject S shuddered at the machine’s resemblance to their Blaster form skulls.

“This machine will attempt to extract magic from the human SOULs and transfer it to the two subjects,” Gaster explained into his recorder. This was a monumental day.

 The subjects clutched at each other but Gaster paid that no mind. As long as they didn’t delay when he needed them, he didn’t care.

“Test one, starting now,” he turned the key and the machine hummed to life.

 Subject P looked startled and Subject S grew wary as the wires coming from the machine started glowing.

 Then, something went wrong. Right when he was about to order Subject S into the machine, there was a bang. Something came loose and the room was flooded with magical energies.

 Gaster swore and tried to shut it all down. He cursed and spat as the machine didn’t seem to want to follow instructions.

 It stopped with a huge, room rattling crash! A large coloured wire came loose and dropped towards him.

 Gaster froze. Then he was knocked out of the way by something with large, bony paws. There was a yelp and a flash.

* * *

  When Gaster’s vision cleared, he could see Subject P lying atop him. Subject P gave a whine before stumbling to its feet.

“Hurry up,” Gaster huffed. Subject P was not light. And where was that lazy Subject S? He expected the other Subject to come running as it always did when something happened to Subject P within earshot.

 Subject P gave a cry, having spotted something in the corner of the room. He dashed off, shifting mid-run into its bi-pedal skeleton form.

“S!” it cried out, skidding to a stop in front of what looked like a fallen skeleton dog.

 Gaster felt a pang of annoyance. If anything happened to Subject S, he would have to start again!

“HE, HE PUSHED ME OUT OF THE WAY,” Subject P whined. It was annoying how it still sounded like a dog even outside of his Blaster form. Made listening to Subject P a chore.

 Gaster crossed his arms as Subject P turned to look at him. He supposed that Subject P was about to blame him for injuring what it saw as its ‘brother’.

“I PUSHED YOU OUT OF THE WAY AND HE PUSHED ME OUT OF THE WAY,” the subject deuced. “THE CABLE FELL ON HIM. IT COULD BE A MAGICAL OVERDOSE AS WELL AS STRUCTURAL DAMAGE.” Gaster stiffly nodded in agreement, surprised that the subject remembered the last time one of them ended up almost falling.

 Subject P looked up at him with eyes glowing.

“YOU’RE THE ‘GREAT W.D. GASTER’, RIGHT?” Subject P said strongly. Gaster realised that the subject must have overheard one of his rants about the ignorant apprentices Asgore sent him. “THAT MEANS YOU CAN HELP ME FIX HIM!” He tried to heft up the form of Subject S. Gaster could see that S’s blaster form was much larger than P’s bi-pedal form. P still grunted and tried to lift him before letting go and stepping back. “OKAY, LET’S TRY THIS!” P pushed out with his magic and Gaster moved to stop him, however, he was stopped by the sound of a ‘PING’.

 S’s SOUL appeared. It was blue.

 Blue magic? P had learnt to use blue magic?

 P paid little attention to him as he magically carried S’s form before him, heading towards the lab where the magical extraction machines were stored.

 Gaster stood for a few moments, brain trying to catch up with everything.

“DR. GASTER! HURRY!” P said to him before leaving the room. Gaster turned, coat flapping out behind him as he followed his subject down to the labs.

…for the first time, he felt like the assistant. It was a strange feeling. He watched in awe as P quickly moved around the lab, hooking S up to everything and getting everything ready for him.

 Had P learnt all of this just from watching him during numerous experiments? It was amazing.

 Gaster felt a strange feeling flutter in his SOUL. A new feeling.

“WE’RE READY!” P announced, looking at him expectantly.

 Gaster felt he couldn’t let this SOUL down. He couldn’t let S down either. He stepped forward.

* * *

 When S opened his eyes, something had changed. Gaster could feel it and he knew S could feel it too.

“S!” P cried out happily, grabbing his hand as he shifted back.

“p,” S responded in a glad but weak voice.

 Gaster could see the moment S looked past P and spotted him. S’s bones rattled for a moment.

 But then Gaster stepped forward. He had been thinking while S had been recovering.

“I’m… glad you’re okay, S,” he said.

 The light in S’s eyes flickered in surprise. Gaster’s SOUL ached. Had he ever shown concern towards these two before?

“what?”

“YES! I AM GLAD YOU ARE ALRIGHT, DON’T SCARE ME LIKE THAT AGAIN!” P said. That was normal P.

“…doctor?”

 Gaster almost couldn’t look at him. He had hurt this subject – no, this child, too many times to count. If he lost S or P, he couldn’t make another, could he? Any subsequent subjects wouldn’t have either monsters’ personalities or experiences.

 He grabbed his equipment to check S over and then shoved both of them back in their cage. He tried to ignore the thoughts floating around in his head. The… pride… he had felt at seeing P rise to the occasion.

 He couldn’t deny it. Without P, S would be dust by now. S only had 1HP.

 He rubbed his face furiously as he realised;

“I can’t keep calling them ‘S’ and ‘P’, can I?” He had never told them where those initials were from. Maybe now he would.

* * *

 Gaster grabbed some clothes from the stores and then went back to the lab. He found he couldn’t even wait the night before getting those children out.

“mornin’ already?” Sans commented as he switched on the light and stormed up to their cage. “what are those, doctor?”

“Clothes,” he responded, “your new clothes.”

“mine?” Sans seemed confused. The two had never been told that anything was theirs.

“NEW CLOTHES?” P questioned curiously. “WHY?”

“Because…” Gaster took a deep breath. “Because I want you to come live with me.”

 The two skeleton children looked up at him with indescribable expressions. They seemed frozen and Gaster’s SOUL ached again.

 Maybe… maybe it was too late?

“But… I guess, if you don’t want to, I could find another monster to take you in.”

“WHAT? I THOUGHT WE ALREADY LIVED WITH YOU?” Papyrus questioned innocently.

 Sans nodded his hesitant agreement, scared of being wrong.

 Gaster was kicking himself for not realising just how little world experience these two had. He would have to work hard to fix that.

 But, first there were new clothes. He had a moment in the store when he realised he had no idea what kind of clothing the children would like and so had bought a lot.

 He laid out striped shirts of all kinds of colours and a few hats, shoes, socks, scarves and pants.

 Sans and Papyrus stared at the clothing in shock.

“FOR US?” Papyrus questioned, barely able to contain his glee.

“Anything you like,” Gaster said, realising with a shock that he meant it. He had done terrible things to these two children and found he wanted to try. To try and ‘be a good person’.

 Sans pulled on a blue shirt with a green stripe and Papyrus went for a red shirt with a yellow stripe. Papyrus decided against shoes because ‘they pinched his feet’. Sans managed to get him into a pair of yellow gumboots and Gaster hid a chuckle at the dissatisfied expression on Papyrus’ long face when he got the boots on.

 They both chose pants and then announced they were done.

 Gaster looked down at them. Sans with his round face and frame, standing there with a wary expression on his face. Papyrus with his long frame, waddling a little in his new boots.

 They were very much children.

“Follow me,” he said, leading them out of the labs.

* * *

 Sans and Papyrus were amazed at everything outside. Gaster was exhausted from questions by the time they reached his residence. He flopped onto his bed after showing the children their rooms – they would go shopping for things to put in them tomorrow.

“doctor…” Sans said hesitantly from the door. It was a soft sound which Gaster would have missed had he actually been sleeping.

 He pulled himself up and motioned the small skeleton towards him.

“why can’t i be with p anymore?”

 Gaster groaned. He had made a mistake, hadn’t he? He thought the children would like their own rooms after the cell but apparently, they had assumed this meant they weren’t to be together.

“If you want to share a room with Papyrus then go ahead. I just thought you would like your own space.”

“papyrus?” Sans questioned.

 Gaster sighed. He just kept failing at this, didn’t he?

“Papyrus is P’s full name. He’s named after his font.”

“oh. do i have a full name?”

“Sans.”

“sans,” Sans repeated, pointing to himself. He turned to the doorway. “and papyrus?”

“Yes. Now, did you want to sleep in Papyrus’ room?”

“yes, doctor.”

 Gaster pulled himself to his feet and guided Sans to the room, asking Papyrus if he was okay sharing a room with his older brother. He also had to tell Papyrus about his and Sans’ names.

“OF COURSE DOCTOR GASTER!” Papyrus said with excitement. He practically pulled Sans into his bed.

 Gaster was ready to leave when Papyrus tugged on his sleeve. He held up a book. It was an old chapter one from Gaster’s pre-Royal Scientist days.

“UH… THE GREAT W.D. GASTER? COULD YOU READ THIS?”

“You don’t have to call me that,” Gaster responded with a sigh. The last thing he needed was other monsters knowing how he referred to himself during his angry rants at the world and idiot interns. “Just ‘Gaster’ is fine.”

 Papyrus nodded.

“GASTER, COULD YOU READ THIS?” he asked again.

 Gaster hesitated for a moment. Then he caught the worried look on Sans’ face and the light flicker of orange in Papyrus’ eyes.

“Okay.” It would be a good idea to start educating the children. He had no idea how much about the world they actually knew.

* * *

It had been a few turbulent months but things were finally starting to settle down for the Gaster family. Gaster still found it a little weird when people called them a family and he could tell that Sans felt the same way. Papyrus, however, took to it like a duck to water. It was amazing how that kid could roll with the punches. It seemed no matter what happened, nothing could faze him.

Except their jokes.

“knock knock,” Sans said.

“NO SANS, NO MORE!” Papyrus whined holding a pillow to his head.

“aw, come on, bro. just one more.”

“NO! NO MORE JOKES, NO MORE PUNS!”

“He’s right Sans,” Gaster commented. He grinned and Sans did the same thing. Gaster’s grin could only mean one thing. “IT’SNOW TIME FOR JOKES.”

“AHHH!” Papyrus groaned.

“that was an ice one, g,” Sans snorted. They grinned at each other. Papyrus’ over-the-top reactions really made this fun.

“AHHH, SANS! GASTER! NOOOO!” Papyrus moaned. “YOU’RE BOTH SO COLD!”

 There was silence for a moment. Then Sans chuckled. Gaster followed him into laughter. Papyrus tried to be stony-faced before he too gave in and started laughing.

* * *

 Where had Sans gone?

 Papyrus was content with his chew toy, letting out happy barks whenever it squeaked, but Sans has vanished the moment Gaster turned his back. As a skeleton child, Sans was usually easy to locate. As a skeleton blaster puppy, Sans could be anywhere.

 Gaster searched the whole house and even the lab in the shed. Papyrus followed him around, bring the toy with him. His tail wagged happily so he didn't appear distressed at Sans' absence.

"Sans! Get out here right now!" Gaster yelled into the air, tired of searching. "Sans!"

 But no one came. Gaster was starting to get very worried.

 Papyrus sniffed the ground and trotted off back towards the house. Gaster followed as he didn't want to lose another child this day.  Papyrus looked around the house and placed his toy neatly on the table before sniffing around the couch.

"Don't tell me," Gaster sighed, quickly figuring it out. He walked over to the couch and knelt down and pressed his face to the ground.

 There was Sans. Asleep under the couch in his blaster form.

 Papyrus yipped loudly. Sans startled awake, knocking his head against the bottom of the couch.

 Gaster heard a familiar whine, a sort of powering up sound. He swore and quickly picked Papyrus up, moving him away from the couch just as a large blue laser blasted out, leaving a hole in the wall and the couch oddly untouched.

 Sans crawled out with an apologetic whine. Both boys shifted back.

"HE DIDN'T MEAN IT," Papyrus said, clutching at Gaster's coat.

"gaster?" Sans questioned hesitantly. When he didn't respond, Sans tried again, worried, "doctor?"

"...you took out the wall," Gaster stated, looking at the hole. He was ecstatic. "Amazing!" Where had all this power been while they were in the labs? Maybe it had something to do with increased experiences and-

"then, i'm not in trouble?" Sans questioned, stopping Gaster's trail of thought. Gaster reminded himself that he wasn't going to study his children. Not again.

"Nah." He blew up enough things at the lab that this was only a small blip compared to the rest of his life. "But you're going to help fix it."

"oh, can i get a screwdriver?" Sans asked excitedly.

"Sure. We could get you a whole kit if you want."

"WHAT DO YOU WANT A SCREWDRIVER FOR?" Papyrus questioned.

"Sans?" Gaster questioned when the child didn't respond.

"agh! it's the perfect moment for a pun but i can't think of any!"

"SANS, NO."

"well, duh! i've got joke-block." Sans said it like it was the end of the world.

"Maybe we should get you a hammer instead," Gaster commented. Both boys looked at him blankly. "So you can smash the block?"

Papyrus gave him a dirty look and squirmed in order to be put down while Sans gave a sympathetic chuckle. 

* * *

“a crab apple a day keeps the gaster away,” Sans sung, having adapted an old saying just to bug the current royal scientist.

“I should try that,” one of the interns commented. Gaster glared at them.

“Do not encourage him,” he said. The intern swallowed in fear. Good.

 A Crab Apple dropped onto Gaster’s head. He wasn’t going to question how it got there. There seemed to be more side-effects to Sans’ accident than he had originally thought. Like the ‘pranking through time and space’ as Papyrus called it. While Gaster originally thought it was a stupid way to refer to it, Papyrus’ title for it grew to make sense as time passed and Gaster gathered more observations of Sans' strange ability.

“Sans!” he scolded.

“wasn’t me,” Sans shrugged, hopping off the bench and dashing off.

 Gaster sighed as he left. He trusted Sans and Papyrus to run around the labs more than he trusted the interns. He had thought that the boys wouldn’t want to return but, for some reason, they often came to visit him in the labs.

 They weren’t supposed to but, what Asgore didn’t know wouldn’t hurt him. Besides, Gaster would bet that Asgore wouldn’t mind at all.

“You really need to keep those two boys out,” another intern commented in an angry voice. “Papyrus almost toppled my experiment.”

“I’m sure he didn’t mean to,” Gaster commented, although he was making a mental note to get rid of this intern. Mistakes and stupidity, he could put up with. Insulting either of his boys, both who were smarter than this stupid intern, was a one-way ticket out of the labs.

“Are you sure?” the other intern questioned. Gaster liked this one. He indulged the boys when they asked questions.

“He said something about how my experiment wouldn’t work but he’s just a child,” the intern shrugged, “what could he know?”

“More than you, obviously,” Gaster growled. He asked the intern for his reports. Then he frowned. He read them again. “A lot more than you. You better go shut this experiment down before it explodes.” Just as he said that, there was the sound of a distant explosion.

 The intern scrambled away.

“wow. the interns do get stupider,” Sans commented from inside the cabinet, pushing the door open.

 The nice intern jumped in shock. “How-“

 Gaster wasn’t going to question it. Sans just did stuff like this, for exactly that kind of reaction.

“Sans, stop ribbing the interns.”

“right. that's your job.”

“Indeed.”

“can’t i rib them just a little? i mean, i do have little ribs.”

 The intern snorted and Gaster looked up at the smiling, round face of his oldest. He couldn’t say ‘no’, could he? Not to that face. Or pun.

“Just a little.”

* * *

 Why wasn’t he surprised when he later heard that Sans had gone and hit an intern over the head with a rib?

“they said papyrus was ‘a lab accident waiting to happen’. they were mean.”

“I understand and the intern will be punished. But, there’ll be no desert tonight.” He saw the smirk Sans gave Papyrus. “What?”

“oh, i think i’ll get desert,” Sans commented.

“No,” Gaster said.

“BUT… I THOUGHT WE WERE HAVING NICE CREAM TONIGHT,” Papyrus said sadly.

Things Gaster learnt about Sans and Papyrus:

Point One: Sans was trouble.

Point Two: Papyrus was a surprisingly good actor.

Point Three: Their eager faces were the only things to make his SOUL waver.

“Fine,” he huffed, stomping off to locate the nice cream vendor.


End file.
